The answers are great. Push-ups, pull-ups, squats, wall climb, curl-ups with the hips at 90 degrees, standing lunge, and one that I especially like, prone hip extensions with no movement in the pelvis.

Push Ups - all kinds
Dynamic Up/Down (going from a plank position to a push up position)
Burpees including variations
Muscle Ups
Single Leg Squat & Touch (reaching out to touch an object on the floor in front of you (medicine ball works great)